The present invention generally relates to an enclosure for encasing and protecting an electrical device, and in particular to a liquid-proof structure of an electrical device enclosure.
Electrical devices, such as printed circuit boards, have been widely used in a variety of applications, including control, detection, power conversion/regulation, and communication. For example, a control unit of a lighting device comprises a power conversion/regulation controller and a photo switching circuit. A lot of electrical/electronic elements are included in the circuit. To ensure proper operation of the control unit, protection of the electrical/electronic elements from severe environments must be exercised.
Conventionally, an electrical/electronic device is protected by being encased in an enclosure made of insulation material. Such enclosures are in general not water proof. In other words, such an enclosure cannot prevent water from penetrating into the enclosure. The humidity may damage the electrical/electronic device encased in the enclosure.
To be operable outdoors, an electrical/electronic device must be protected by water-proof enclosures. To ensure water-proofness, fusion caused by ultrasonic welding is employed to seal parts of the enclosure together. However, the sealing formed by fusion may deteriorate after a long term use, resulting in water leakage into the enclosure. Sealing formed by other means may also surfer the same problem.
An approach to solve the leakage problem is to completely encase an electrical/electronic with resin materials. Excellent water-proofness can be achieved. However, encasing an electrical/electronic device with resin materials is very expensive and may substantially increase the overall weight of the electrical/electronic device. Furthermore, high temperature resulting from injection of the resin materials onto the electrical/electronic device may damage temperature sensitive electrical/electronic elements. In addition, completely encasing an electrical/electronic device with resin materials hinders repairing or replacement of parts of the electrical/electronic device. The resin materials may also cause environmental problems.
It is thus desirable to provide a liquid-proof enclosure for electrical/electronic device for overcoming the above-discussed problems.
Accordingly, an object of the present invention is to provide a liquid-proof enclosure comprised of a plurality of casing members, rib-slot pairs being formed between the casing members for increasing the length of a possible leakage path between the casing members and more effectively preventing liquid from penetrating into the interior of the enclosure.
Another object of the present invention is to provide a liquid-proof enclosure which is capable to achieve liquid-proofness without injection of resin material therein.
A further object of the present invention is to provide a liquid-proof enclosure which allows replacement/repairing of an electrical device encased therein.
In accordance with the present invention, a liquid-proof enclosure comprises first and second casing members engaged with each other to define an interior space therebetween for receiving, retaining and protecting an electrical device. Each casing member has a mating flange engaging each other to encase the electrical device. A rib is formed along the mating flange of the first casing member and a corresponding slot is defined along the mating flange of the second casing member for receiving and engaging the rib thereby attaching the first and second casing members together and increasing the length and thus effecting blockage of possible leakage path between the first and second casing members. An opening is defined between the first and second casing members. At least a circumferential slot is defined along a circumferential side wall of the opening. A cable retainer retaining a cable forms ribs received in the slot of the opening for attaching the cable retainer to the first and second casing members and to prevent liquid leakage into the enclosure.